THE SMALL-MAMMAL PROBLEM 741 



Where rats are very numerous, apply twelve months of intense 

 slaughter, which will bring the problem within manageable 

 limits ; then apply the Rodier system. Its great merit is the 

 lengthy period of neglect that an area well in hand can sustain 

 before becoming, if it ever does become again, a nuisance ; its 

 defect is solely the difficulty of execution. Rat-poisoning must 

 cease, and rat-killing as a sport must be banned, though a 

 careful man may shoot with safety rats carrying food, as the 

 does alone perform this duty." 



Mr E. Read, chief of the Rats Branch of the Ministry of 

 Agriculture and Fisheries, has been kind enough to inform 

 us of a method, discovered by the work of his department, 

 by which the Rodier system can be applied in a practical 

 and wholesale manner, without the initial trouble of capturing 

 the rats alive and determining the sexes. During the earlier 

 winter months, e.g., November, poisoning with a preparation 

 of liquid extract of squill and milk has been resorted to, and 

 many thousands of rats have been killed in all parts of the 

 country by this means. Of the total number killed in this 

 way at this season, no fewer than 85 per cent, were females, 

 the milk proving to be an irresistible bait for the does nursing 

 families at the onset of the inclement season. The Rodier 

 system deliberately and generally applied could show no better 

 result than this, because even with it, accident and error in 

 the determination of sex would certainly lead to the death of 

 many males. From this experience it would appear that active 

 rat destruction should take place chiefly in the winter months 

 when the does are hard pressed ; the other months should be 

 used chiefly for preventive work such as rat-proofing. 



Scientific study confers a measure of foresight, and it is 

 often possible to predict many of the consequences which 

 must flow from current actions. The small-mammal problem 

 is one of the things pre-eminently susceptible to treatment by 

 intelligent anticipation, and with our knowledge and experi- 

 ence, we certainly ought not to be content with merely devising 

 expedients to cope with the difficulties of to-day, heedless of the 

 perils of to-morrow. Given sufficient determination, money, 

 and patience, we might, in the course of time, succeed in 

 exterminating both species of rat and the House Mouse in 



